Three-Dimensional Phase-Contrast MR Angiography at 5 T Assesses Warming-Associated Changes in the Visible Hand...

Thermal challenge can reveal vascular abnormalities in systemic sclerosis (SSc), but current assessments primarily measure surface temperature or cutaneous perfusion. Warming-associated changes in the visible three-dimensional hand vascular network in SSc remain incompletely characterized.

To quantify warming-associated changes and group differences in hand-size-normalized metrics of visible hand vessels using 5-T three-dimensional phase-contrast MR angiography (3D PC-MRA), and to assess repeatability and reader agreement.

Prospective case-control study.

Ninety participants (60 SSc, mean age: 44.00 ± 10.73 years, 55 females; 30 healthy controls, mean age: 42.83 ± 13.24 years old, 28 females). Twenty controls (18 females) underwent baseline scan-rescan imaging; reader agreement was assessed in the 60 baseline examinations.

5 T; noncontrast-enhanced 3D gradient-echo PC-MRA.

Hands were imaged before and after 5-min immersion in 40°C water. Hand-size-normalized metrics were vessel volume (nVol), centerline length (nLen), and apparent vessel radius (nRad); changes (Δ) were post-immersion minus baseline.

Paired t-tests or Wilcoxon signed-rank tests; Welch t-tests; multivariable linear regression adjusted for age, sex, body mass index, and baseline values; intraclass correlation coefficients (ICCs); and Bland-Altman analysis. Significance was q < 0.05 after Benjamini-Hochberg correction and p < 0.05 otherwise.

Normalized vessel volume and normalized centerline length increased significantly in both groups, with mean changes of 0.76 × 10^-3 and 1.91 in controls and 1.80 × 10^-3 and 4.80 in SSc, respectively. Adjusted increases were significantly greater in SSc for normalized vessel volume (between-group difference, 1.11 × 10^-3; 95% CI, [0.36-1.85] × 10^-3) and normalized centerline length (difference, 1.97; 95% CI, 0.36-3.59). Changes in normalized apparent vessel radius did not differ after adjustment (difference, -0.001 × 10^-3; q = 0.996). Scan-rescan and reader-agreement ICCs were 0.948-0.994 and 0.941-0.993, respectively.

At 5 T, 3D PC-MRA detected greater warming-associated increases in nVol and nLen in SSc than controls. Baseline measurements showed good-to-excellent scan-rescan repeatability in controls and excellent reader agreement.

Stage 3.